1. Field of the invention
The present invention is related to a process for combining micro-coaxial cables and pins by riveting, and especially to a process by which the end of a micro-coaxial cable is dealt with by cut stripping by pushing in a pressing guide wheel, and then a pin is connected therewith by riveting to form a combination structure of the micro-coaxial cable and the pin with high structural stability.
The micro-coaxial cable stated in the present invention is mostly composed of a cable, the outermost diameter thereof is about 0.6 mm, the diameter of the central conductor thereof is about 0.15 mm. It is widely used on products of high precision such as a bus for a computer main frame.
2. Description of the Prior Art
Such micro-coaxial cable 10 as shown in FIG. 1 is comprised mainly of an inner central conductor 11, an inner insulation layer 12, an external conductor layer 13 and an external insulation layer 14. Wherein, the external conductor layer 13 is used mainly for preventing generating EMI (electromagnetic interference) when the inner central conductor 11 is electrically connected to transmit signals. Such cable is integrally formed as a long strip when in manufacturing, thereby, it must have its end cutting stripped to reveal the inner central conductor 11 and the external conductor layer 13 ready for combine with a pin and a grounding plate.
Take the micro-coaxial cable 10 with an outermost diameter of 0.65 mm as an example, the thickness of the external insulation layer 14 is 0.06 mm; the diameter of the external conductor layer 13 is 0.53 mm, the thickness of it is 0.05 mm; while the diameter of the inner insulation layer 12 is 0.43 mm, the thickness of it is 0.05 mm. That is to say, in cutting stripping the end of the micro-coaxial cable 10 to combine the exposed inner central conductor 11 thereof with a pin or a grounding plate, radial cutting thickness thereof is very small. End processing of such micro-coaxial cable 10 is generally deemed hard to be success by the end cut-stripping technique available presently. Therefore, the micro-coaxial cable 10 is unable to be processed by riveting in production.
Therefore, very few advanced countries have practiced such processing of such micro-coaxial cable with a laser welding system. According to practical experience of production, inferiority rate of products made with such a laser welding system is as high as 30%. This is mainly because that design of pins basically takes consideration in riveting rather than welding, flexibility resulted from laser welding is bad, contact of pins with the end of a connector board is subjected to separation (bad contact) by vibration. And products made by a laser welding system have the latent problems of difficulty for mass production and instability in signal continuation.
Moreover, such laser welding process is very complicated and troublesome, FIG. 1A shows the process flow of it, that includes:
A. a micro-coaxial cable 10 is cut into desire lengths;
B. a lot of micro-coaxial cables 10 are arrayed in a desired width to form a bus;
C. the bus made in the process B and to be processed is adhered with a thin film 101 both on the upper and the lower surfaces thereof;
D. a partial area W on the abovementioned external insulation layer 14 near the end of the bus is processed by stripping operation to reveal the external conductor layer 13 in a mode of aerification by heat collecting in laser irradiation;
E. the stripped area in the process D is welded to a grounding plate 102;
F. in the mode of aerification by heat collecting in laser irradiation as stated in the process D, the external insulation layer 14 in the front of the grounding plate 102 is processed by stripping operation; this processing mode induces overly high temperature due to larger thickness of the bus processed in the mode of aerification by heat collecting in laser irradiation, it can not reveal the inner central conductor 11 by one time cutting and stripping in consideration of preventing the inner central conductor 11 from damage.
G. this process includes removing the external conductor layer 13 to expose inner insulation layer 12 by man-power trimming or bending to and fro, the inner insulation layer 12 then is tidied to be neat and ready for the next process;
H. then the inner insulation layer 12 is processed by stripping operation in a mode of aerification by heat collecting with a laser device to reveal the inner central conductor 11;
I. the exposed inner central conductor 11 is processed with tin dipping;
J. a plurality of such inner central conductors 11 with the dipping tin layers 104 are inserted into pins in a housing 105;
K. the half-made product which has been primarily assembled is processed by end welding, and the final process of tidying for being neat can be completed.
The conventional laser welding process for a micro-coaxial cable not only requires multiple times of laser processing, but also is time consumptive, and the operation of removing the external conductor layer 13 by man-power trimming or bending to and fro is very bothersome and time consumptive. The products made do not have any moving tolerance by that a joint 106 (referring to FIG. 1, process K) at the revealed end of the micro-coaxial cable is deadly welded to the grounding plate 102, hence flexural resistance thereof is very bad. This may result a large mount of inferior products with broken connection by the reason that operators bend the housings 105 during the process of assembling.
In the presently available cable end processing machines, mostly they are for stripping conductors of common sizes; they do not suit such end cutting stripping of the micro-coaxial cable. The existing cable end processing machines mostly make their two mutual opposite knife seats of a cutting device move to and fro in a straight line and have them driven by a single compression cylinder, the two knife sets can thus cut into the insulation layer of a conductor for skin stripping. However, the thickness of each external constructing layer of the micro-coaxial cable is very small, if the cutting machine using the single compression cylinder has a slight error in the sizes of the constructing members or the set distance, the knives cannot precisely cut into the external layers of the central conductor. By the limitation of the existing cable end processing machines, the techniques for combining micro-coaxial cables and pins by riveting are very difficult to get success.
The object of the present invention is to provide a process for combining micro-coaxial cables and pins by riveting, the process includes the steps of:
(1) a cable is directly cut and stripped at the related area after the desired length of the cable is obtained by cutting;
(2) a pin is riveted onto the end of the cable;
(3) a plurality of such cables and pins processed are placed in a plastic housing to form a bus;
(4) the bus is welded to a grounding plate;
(5) the bus is arrayed and tidied to be neat to complete the process.
By the process for combining micro-coaxial cables and pins by riveting, the whole process flow can be effectively shortened, and suits fast mass production with lower cost, the micro-coaxial cables and the pins can be more excellently and stably combined.
To obtain the object, the present invention is provided at least with a cable-end processing machine; a pair of mutually opposite knife seats are provided on a surface of a rotary disk, a pressing guide wheel is provided in opposition to the rotary disk to make precise radial cutting of the mutually opposite knife seats in moving along and by guiding of a conical inner surface of the pressing guide wheel. So that the external layers of a cable can be accurately stripped to reveal the inner central conductor at the end, then the cable is sent to a riveting apparatus to proceed to combination of the micro-coaxial cable and the pin.
The above riveting apparatus is preferably joined integrally in the above cable-end processing machine in order to do automatic mass production.
The present invention will be apparent in its novelty and features after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.